Process of preparing dust ores for blast-furnaces.



UNITED STATES PATENT @TTTQE.

HEINRICH ERNST ESCH, OF GIESSEN, GERMANY, ASSIGNOR TO THE FIRM OF FELLNER & ZIEGLER, OF FRANKFORT-ON-TI-IE-MAIN, BOGKENHEIM, GERMANY.

PROCESS OF PREPARING DUST ORES FOR BLAST-FURNACES.

No. 801 ,143. Specification of Letters Patent. Patented Oct. 3, 1905. Application filed May 1, 1905. Serial Nov 258,392.

T whOm it y 677): The operation of this improved process is Be it known that I, HEINRICH ERNST Eson, similar to that of the process described above, a subject of the German Emperor, and a resiand reference is herewith made thereto. dent of Griessen, Germany, have invented cer- Many ores in the form of ore-dust are highly 5 tain new and useful Improvements in Procdesirable to be reduced and for this reason esses of Preparing Dust Ores for Blast-Furadvantageous to be transformed from their naces, of which the following is a specificadusty state to agglomerated masses or balls. tion. Hitherto, however, owing to the high fusi- This invention relates to the well-known bility of certain ores-as, for instance, Swe- 10 process of preparing iron ores of fine grain dish and other magnetic iron ores-it was exand sandy texture, or ore-dust, for the blasttremelydiflicult to cause their agglomeration furnace, which consists in forming such oreor fusion, and if such was actually accom- 5 dust into agglomerated masses or balls, so as plished it was only by the use of a comparato utilize thereby the iron-ore dust hitherto tively large supply of fuel and heat, and there- I5 but seldom used, owing to the disadvantages fore commercially impracticable.

accompanying its use in the blast-furnace. The object of the present invention is to bring Iron-ore dust is obtained, first, by the hanore-dust obtained from ores of high fusibility 7 dling of hard iron ores for the blast-furnace, intothe desired form applicablefor their workby which small splinters are broken off and ing in the blast-furnace by agglomerating the 2 dust is formed; secondly, as by-products in same by means of the heat produced by an igcertain processesas, for instance, the procnited stream of coal-dust. ess of manufacturing sulfuric acid; thirdly, For this purpose the invention consists in by the preparation of certain ores for the feeding ore-dust of high fusibility to the inblast-furnaceas, for instance, the valuable going end of an inclined rotatable furnace, sub- 5 spathic iron ore, (ferrous carbonate,) which jecting said ore-dust to a gradually-increasing being subjected to heat is decomposed, whereheat during its passage through the furnace, by carbonic acid is liberated and the ore fusing and agglomerating said ore-dust tocaused to crumble to dust; fourthly, in the gether with an easily-fusible material only at operation of many blast-furnaces large quana definite part of the furnace, and removing 3 tities of ore-dust are carried away by the curthe agglomerated masses at the outgoing end rent of waste gases and collected in the tubes of the furnace. and fines of the blast-furnace, and, lastly, The invention consists more especially in 5 many ores occur in nature in soft, earthy, and subjecting the ore-dust of high fusibility for loamy form. These ores and others herein fusing, agglomerating, or slagging the same 35 not specially referred to contain such large to an ignited stream of coal-dust mixed with quantities of iron that their metallurgical rea flux or material of low fusibility; and the duction becomes highly desirable and profitinvention consists, lastly, of mixing with the 9 able. The said known process overcomes coal-dust of theignited stream aneasily-fusible these inherent disadvantages and consists in ore and projecting the ignited particles of 4 feeding the ore-dust to the ingoing end of an coal-dust mixed with the particles of ore-dust inclined rotatory furnace, subjecting said oreagainst the ore-dust of high fusibility passing dust to a gradually-increasing heat during its through the furnace. passage through the furnace until agglomera- To carry out my invention, ore-dust is fed tion or slagging takes place, and removing the in quantitively exact portions into the upper 45 agglomerated masses at the outgoing end of end of an inclined rotatable furnace and owing the furnace. to the rotation of the furnace and inclination The presentinvention is differentiated from of the same is gradually moved from the up- I00 the said process in embodying the feature of per end of the furnace toward the lower end. agglomerating ore-dust of high fusibility, An ignited stream of combustible gas, prefer- 5 which is not readily capable of being fused ably coal-dust, impinges against the ore-dust or agglomerated, by the employment of the near the lower accessible end of the furnace, process described above or by other means the burning particles of coal of the stream of 5 hitherto proposed. coal-dust being projected against the ore-dust,

which is caused to be heated to a considerable extent, but owing to its high fusibility prcvented from being fused or agglomerated with parts of the ore-dustin the furnace. By means of the intimate contact of the projecting burning particles of coal-dust with the particles of ore-dust in the furnace the resulting ashes of the coal-dust mix with the particles of oredust and serve as a flux tending to aid the fusion of the same. The radiated heat of the ignited stream of combustible gas or coaldust, as the case may be, subjects the ore-dust of the upper not accessible part of the fur-- nace to a process of drying, calcining, and preheating. In order to effect the fusion of this heated ore-dust of high fusibility, quantities of a material in dusty form are brought into the zone of agglomeration, which either serve directly in energetically assisting the agglomeration of the ores of high fusibility or by their own fusion or agglomeration cause the mutual adhesion of the particles of ore-dust in the lower end of the furnace, and thereby the baking of the ore-dust resisting fusion or agglomeration in such a manner that it is formed into lumps, bodies, or hard broken pieces and ready to be discharged from-the furnace in this state.

In the execution of the process the additions intended to serve as flux or binding material are intimately mixed with the coal-dust intended for the ignited stream and are projected against the ore-dust or may also be by means of a special supply device forced into the furnace with the comb ustion-air. A preferable form of execution of the improved process is to add to the coal-dust or to the combustion-air of the ignited stream an easilyfusible oreas, for instance, easily-fusil. le brown hematite or brown iron ore or the by-products had by the preparation of iron or manganese ores (ore slimes) or by mixing easily-fusible iron slags in dusty form and then directing the same with the burning coal particles toward the critical point in the agglomeration zone of the furnace. The easilyfusible ore intimately mixed with the burning coal fuses on its way to the ore-dust of the furnace in the ignited stream and encounters in this partly-fused or fused condition the ore-dust in the furnace. This fused ore serves for inciting a certain agglomeration of the ore-dust and causing thereby the fusion and slaggmg of the same, its principal action,

however, being that it acts to a certain extent as a binding medium, which binds that not yet entirely agglomerated or fused ore-dust into large pieces, lumps, or layers, forming crusts along the interior walls of the furnace. If the latter should form, they may be readily removed in the known manner.

WVhen it is desirable to utilize the flue-dust of the blast-furnace consisting of iron-ore in dusty form and particles of those materials charged to the blast-furnace with the ironore in order to effect its reduction, it is necessary to bring the flue-dust into a form applicable for its reduction in the blast-furnace. This is done in the case of flue-dust of high fusibility by feeding the same into the upper end of the inclined rotatable furnace in the known manner and causingits agglomeration at the critical point of the rotatable furnace. Flue-dust of low fusibility is utilized by mixing the same with the coal-dust particles intended for theignited stream and projecting the ignited stream of this mixture against the ore-dust passing through the rotatable furnace, and thereby causing its agglomeration.

Having thus described my invent-ion, Iclaim as new and desire to secure by Letters Patent 1. The process of preparing ore-dust of high fusibility for the blast-furnace which consists in feeding the ore by a rotating advancing action first through a region of graduallyincreasing heat, and then into a region where it is subjected to a stream of ignited fuel mixed with an easily-fusible material, thereby agglomerating it, and finally removing the resulting agglomerated masses.

2. The process herein described of preparing ore-dust of high fusibility for the blastfurnace which consists in feeding the ore-dust by a rotating advancing action first to a region of gradually-increasing heat, then into a region where it is subjected to a stream of ignited coal-dust mixed with an easily-fusible ore-dust, thereby agglomerating it in said region, and finally removing the resulting agglomerated masses.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HEINRICH ERNST ESCH.

\Vitnesses:

FRANZ HASSLAOHER, EewIN DIPPEL. 

